Take a few minutes and turn the adjustment both ways. Work in 1/4 turns Sight down the neck and see what happens each time you adjust it. Pretty soon you will understand how the truss rod works. If you have a beater, experiment on that. This is not a big mystery. It would be hard to mess up your guitar if you are working in 1/4 turns or less. If the rod is so tight you can hardly turn it then see your technician. Check the care and feeding section on the Taylor sight. I believe they have some good info.
By the way-the ideal adjustment is dependant upon the neck angle and the saddle height. Sometimes flat is the best, sometimes a slight relief is best. If you are scared to do this, use a beater to learn how. Guitars are like kids...they are all different and require slight adjustments to make them the best they can be.
